Resource Categories: Labor, Materials, Equipment, and Supplies

PMBOK v8 Definition

The resource breakdown structure is a hierarchical representation of resources by category and type. Examples of resource categories include but are not limited to labor, materials, equipment, and supplies. Resource types may include the skill level, grade level, required certifications, or other information as appropriate to the project. This structure is documented in the resource management plan, which identifies methods for identifying and quantifying the team and physical resources needed.

Why It Matters for the Exam

This concept appears frequently in Planning process group questions, particularly those involving Estimate Activity Resources and Develop Resource Management Plan. PMI exam questions test your ability to distinguish between resource categories (labor, materials, equipment, supplies) and resource types (skill level, grade, certifications). Expect multiple-choice questions asking which category a specific resource belongs to or which document captures this hierarchical breakdown.

Key Points to Remember (for the exam)

• Four Core Categories: Labor, materials, equipment, and supplies – memorize this exact list
• Hierarchical Structure: The resource breakdown structure organizes resources by category first, then by type
• Category vs. Type: Categories are broad groups (labor); types are specific attributes (skill level, grade, certifications)
• Document Location: The resource breakdown structure is an output of the resource management plan
• Resource Requirements: Identify the types and quantities of resources required for each work package or activity
• Aggregation: Resource requirements can be aggregated to determine estimated resources for each work package, each WBS branch, and the entire project
• Internal vs. External: Resources can be internal (assigned from functional managers) or external (obtained through procurement)

Typical PMI Exam Example

A project manager is developing the resource management plan for a construction project. She needs to identify all resources required for the foundation work package. Which resource category would include concrete, rebar, and formwork materials?

Answer: Materials – these are physical items consumed during the project, falling under the "materials" category in the resource breakdown structure.

PMI Exam Traps

• Trap: Confusing "materials" with "supplies"

  • Reality: Materials are consumed to create the deliverable (concrete, steel); supplies are consumed to support the work (office supplies, safety gear)

• Trap: Thinking "equipment" includes all tools

  • Reality: Equipment refers to machinery and major tools (cranes, computers); hand tools may be categorized as supplies depending on project context

• Trap: Assuming resource categories are fixed across all projects

  • Reality: The four categories are examples, not an exhaustive list – projects may add categories as needed

• Trap: Confusing the resource breakdown structure with the work breakdown structure

  • Reality: WBS organizes work deliverables; resource breakdown structure organizes resources by category and type

Important PMI Connections

Quick Review Questions

1. List the four example resource categories provided in PMBOK v8 for the resource breakdown structure.

2. What is the difference between a resource "category" and a resource "type" in the resource breakdown structure?

3. In which document is the resource breakdown structure typically included?

4. How can resource requirements be aggregated across the project?

5. What distinguishes internal resources from external resources in project management?

PMBOK v8 Reference

Section 4.3 – Develop Resource Management Plan (Resource Breakdown Structure)